Reactivity of a Sodium Anion with Alkenes: 1‑Electron vs 2‑Electron Reductions

The sodium anion (sodide) is an uncommon alkali metal species, whose reactivity has been scarcely studied, with previous reports limited to decomposition and quenching reactions of ill-characterized species formed in situ. Based on our recent report of the first gram-scale synthesis of a well-characterized sodide complex, [Na⁺(2,2,2-cryptand)]­Na^– (1), we now describe its reactivity with phenyl-substituted ethylenes and a cyclic polyolefin. Depending on the substitution pattern, 1 mediates either 1-electron or 2-electron reduction. Reaction with a cyclic multiolefin, 1,3,5,7-cyclooctatetraene (COT), exhibits two-electron reduction to produce COT^2– species.